I would like to feel the hammers on these guns that people say they cant cock. I'm not trying to be a jerk, but come on... seriously? If your wife truly cant cock the hammer, or manipulate the trigger to get the revolver to fire, what good is it for her to have? I have an SP101-22, my wife has strength issues with her hands, and she has no trouble operating it. I do understand your wife might have more serious issues than my wife.
Perhaps a single action 22 pistol would be a better choice. Something light, and not too small, like a S&W 422, or a Ruger 22/45 LITE. If she cant handle something like that, there isn't anything that she is going to be able to handle. Don't run out and buy her something little and cute, like a Beretta Bobcat, or Ruger SR22, because you will be right back in the same situation. Those guns are Double Action. She also needs something that isn't so small that its difficult to operate.